Philae’s first touchdown seen by Rosetta

blogs.esa.int

88 points·twowo··6 comments

It looks like you can see the lander, up in the air and casting a shadow on the surface in the 2nd image. If it is, you can get a good estimate of its horizontal velocity from the image timestamp.

https://plus.google.com/app/basic/stream/z13gzxiwdkq2clyew22...

That speck appears to be there in the first image as well, though not as bright...?

I wonder if Philae actually landed exactly where computed (the green square), and if so why the dark dust does not radiate from that spot, but "down-wards". Perhaps Philae hit the surface at an angle?

Did the lander somehow adjust itself while hovering away from the original landing site? I can't imagine Philae bouncing away, then flying for roughly one hour (?) and then landing on its feet.

It would land heavy side down both initially and after a bounce, no?

Gravity exerts almost no torque here. Philae has 100 kg of inertia, but it weighs less than a feather.

Even if were in a strong gravity field, that still wouldn't orient it, if there's no force like air resistance to attenuate its tumbling. It can rotate indefinitely in the vertical plane: there's no loss of energy. (In an atmosphere, this rotation is damped by air drag, so gravity can orient things).

It had a flywheel in use at the time, which was used to stabilize its flight relative to the surface, but it induced a spin ..

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